Dust blowers have been used widely to blow dust from precision machines, negative film, etc. In general, a dust blower includes an aerosol spraying can and a valve. The spraying can is filled with liquefied gas as propellant under high pressure and fitted with a nozzle at its top. The nozzle functions as a jet button for opening and closing the valve. A blowout tube is connected to the front end of the nozzle. The dust blower jets gas through the blowout tube to a spot. When the jet button is pressed, the valve is opened, so that the gas in the spraying can passes through the valve and jetted out through the nozzle and the blowout tube.
The liquefied gas may be HFC(hydrofluorocarbon)134a or HFC152a as alternate flon, or DME (dimethyl ether). The liquefied gas is kept under high pressure in the spraying can.
When HFC134a and HFC152a are released into the atmosphere, they cause the greenhouse effect. For this reason, HFC134a and HFC152a are listed as greenhouse effect gasses restricted in output in the Kyoto Protocol adopted to achieve the purpose of the Framework Convention on Climate Change, and the whole industry has been promoting the reduction in the output of HFC134a and HFC152a. For example, the greenhouse effect of HFC134a is 1,300 times more than the greenhouse effect of carbon dioxide, and the greenhouse effect of HFC152a is 140 times more than the greenhouse effect of carbon dioxide. For this reason, it has been demanded that HFC products be replaced by products for use with other compressed gas.
DME, which has a low global warming potential, is combustible gas. And HFC152a is combustible gas, too. These gasses cannot be used for electronic circuit boards and other parts that must be non-combustible.
A dust blower has been proposed that includes a high-pressure liquefied gas bottle filled with liquefied carbonic acid gas, nitrogen gas, or the like in place of HFC.
Patent document 1: JP 2005-249192 A
This dust blower can be used with non-combustible gas having a low global warming potential. However, the high-pressure liquefied gas bottle is expensive, and the gas in it is consumed in a relatively short time. As a result, it is necessary to frequently replace the expensive bottle. The replacement is troublesome and costly.
Another dust blower has been proposed, which includes a high-pressure liquefied gas bottle and is fitted with a pressure reducing mechanism for jetting high-pressure gas while reducing the pressure of the gas in order to lengthen the life of the bottle. Because the pressure reducing mechanism is complex, the dust blower is large and costly.